Half to john h



2 Sheets-Sheet 1.

(No Model.)

B. ETHQMAS.

ROTARY STEAM ENGINE.

No. 370,105. Patented Sept. 20, 1887.

(No Model.) 2 Sheets-Sheet 2.

E. E. THOMAS.

ROTARY STEAM ENGINE.

No. 370,105. Patented Sept.-20, 1887..

EDWIN E. THOMAS, OF MINNEAPOLIS, MINNES OTA, ASSIGNOR OF ONE HALF TOJOHN H. PUTNAM, OF SAME PLACE.

ROTARY STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 370,105, datedSeptember 20, 1887.

Application filed February 19, 1887. Serial No. 229,191.

To ctZZ whom it may concern.-

Be it known that I, EDWIN E. THOMAS, of Minneapolis, in the county ofHennepin and State of Minnesota, have invented certain new and usefulImprovements in Rotary Steam- Engines, of which the following is aspecification.

This invention relates to improvements'in the construction of that classof steam-engines that are usually known as rotary engines. Theseengines, as usually constructed, consist of a cylinder through which ashaft passes, having thereon a piston that extends at one side of theshaft to the wall of the cylinder and a sliding abutment between whichand the cylinder the steam is admitted. The pressure of the steam inthis space moves the piston, and with it the shaft, causing it to rotatein the cylinder. One objection to this construction is that the pressureof the steam against one face of the sliding abutment causes itsopposite face to be pressed against the wall of the recess in which itmoves, thereby creating considerable friction and requiring considerablepower to move the abutment.

One object of my invention is to overcome this objection, which I do byproviding an abutment that is rigidly secured to a pivoted arm, whichholds it against the pressure of the steam and causes it to have apositive movement in the arc of a circle.

Another object of my invention is to provide aconstruction that willpermit the heads of the cylinder to be readily detached and the pistonsto be drawn off from the shaft for the purpose of repacking them.

Another object of my invention is to provide an improved packing for thepistons.

Another object of my invention is to provide the engine with avalve ofimproved construction.

(No model.)

section of the steam-valve in position to admit steam for the forwardmotion. Fig. 6 is a section on line X X of Fig. 9. Fig. 7 is a sectionon line Y Y of Fig. 6. Fig. Sis a section similar to Fig. 5, showing thevalve in position to admit steam for the backward motion. Fig. 9 is aplan view of the valve. Fig. 10 is a section on-line Z Z of Fig. 6.

The engine is provided with a suitable bedframe, 2, which supports thecylinder 3. This cylinder may be of any suitable size, and it ispreferably dividedinto two compartments by a central partition. Thecylinder is also provided at each end with a head, 4, that is securedthereto by bolts 5. The piston-shaft 7 passes through the center of thecylinder and is mounted in boxes formed upon the crossheads 11. Thesecross-heads are bolted to sup ports 13, that extend lengthwise of thecylinder, at each side thereof, and are in turn supported by thebed-frame. A separate piston, 15, is provided in each compartment of thecylinder, and these pistons are secured to the shaft so that they extendtherefrom at its opposite sides, as shown by dotted lines in Fig. 3. Theshaft is provided upon opposite sides with a spline or feather, l6, andthe piston with corresponding grooves. These splines prevent the pistonfrom turning on the shaft, but permit it to be moved longitudinallythereon for the purpose of putting it on or taking it off the shaft. Thepiston projects from one side of the shaft and extends to the wall ofthe cylinder. The piston is provided at its end with a packing, 17, andon each side with a ring-packing, 18, and with a. packing, 19, thatextends from the ring-packing to the end of the packing 17. The packing17 is provided with a screw, 20, which is tapped through it and bearsagainst the piston for the purpose of setting out the said arrangement.The ring-packings 18 are held in place by dowel-pins 21, and are pressedoutward against the heads of the cylinder by springs 22, that are seatedin recesses under the rings and press against their under surfaces.

The thickness of the piston is substantially equal to the width of thespace in the cylinder between its head and the central partition, andthe packing-rings 18 and strips 19 are insorted to substantially theirfull thickness into recesses in the piston.

The packing-strip 19 is held at one end by a dowel-pin, 23, to the endof the packing 17, and is also pressed outward by a spring, 24, seatedbeneath it. The other end of this strip 19 is provided with a shoulde,which laps into a shouldered recess in the ring 18. This constructionenables me to remove the piston from the shaft and adjust the packing 17without breaking the continuity of the packing on the sides of thepiston,as the packing 19 moves with the packing 17, while its end movesin the recess in the ring 18.

. The movable abutment 25 is secured rigidly to an arm, 27, that ismounted upon a pivot, 26, upon the bed-frame. The abutment is in theform of a segment of a circle that is struck from the center of thepivot 26, and the opening through the wall of the cylinder is formedupon a similar curve, so that the abutment has a swinging movement'intoand out of the cylinder. The end of the abutment rests upon the piston,and as the piston rotates the abutment moves into and out of thecylinder, being pressed in by a spring, 28, that bears on the arm 27 andbeing pressed out by the movement of the piston. The spring 28 issecured to a stud, 29, and passes under a lug, 30, that is provided withan adjusting-screw, 33, by which the tension of the spring may beregulated. The abutment passes through a suitable stuffing-box, 34, andis provided upon its opposite faces with the steamway's 35. Steam-ports36 "connect with steam-pipes 37 and extend into the passage throughwhich the curved abutment-passes. When the abutment is out the extent ofits movement, the passage is closed by the inner end of the abutment,which completely fills it. When the end of the abutment is projectedinto the cylinder, a steam-passage is formed from each of thesteam-ports into the cylinder through the grooves in the faces of theabutment.

The operation will be readily understood. Let it be supposed that theparts are in the position shown in Fig. 3 and that steam is enteringthrough the right-hand port into the space between that side of theabutment and the piston. It will then force the piston to move in thedirection of the arrow, while the steam on the other side of the pistonwill exhaust through the other poi-t. To reverse the engine, steam isadmitted through the other port andexhausts through the first, the operation being similar in both cases.

- It will be seen that with this construction the pressure of the steamupon the abutment cannot affect its free and easy movement- By using adouble cylinder and settingthe pistons directly opposite each other onepiston will always be one-half a revolution ahead of the other, and whenone piston is passing the abutment and receiving no steam-pressure theother will be at the half-revolution and will be re ceiving the fullpressure of the steam.

40 may be turned upon its axis by any suitable means applied to the stem41. The valve has a T-shaped port, 45, extendingthrough it in the planeof the three pipes 43 and 37. The main portion of this port has anenlargement, 44, at its end, as shown in Figs. 5 and 6, and thecross-passage with which the main passage connects is on the other sideof the center of the valve from the enlarged end of the main passage, asshown in Fig. 6. When the valve is in the position shown in Fig. 6, thesteamport 45 does not communicate with either of the pipes 37. thendirectly in line with the intake-pipe 43.

By moving the valve about a sixteenth of a revolution in eitherdirection the cross-passage of the port 45 communicates with one of thepipes 37, while the pipe 4 3 still communicates with the enlarged part44 of the port. Turning the valve an eighth of a revolution in theopposite direction carries the port 45 into communication with the othersteam -pipe 37. When the valve is in a position half-way between thesetwo, as indicated 'in Fig. 6, the steam is out oft from both steam-pipes37 and from the engine-cylinder. The exhaust-port consists of aV-shapedpassage, 47, whose ends extend to the periphery of thecylindrical valve on the opposite side of the center from thecross-passage of the steam-port and have a corresponding relation to thesteam-pipes 37, so that when the steam-port communicates with one of thesteam-pipes one of the passages of the exhaust-port communicates withthe other. Both passages of the exhaust port communicate with a passage,49, that leads out through an opening in the wall of the oylindricalsteam-chest. This valve, it will be seen, is very simple in constructionand easily operated, either to shut off the steam or to direct it intoeither port of the rotary engine. The engine may therefore be veryeasily reversed by merely giving a, slight turn to the valve, and allcomplicated devices for accomplishing this result may be dispensed with.1 I claim as my invention 1. The combination, in a rotary engine, withthe cylinder provided with the stuffing-box '34, of the arm 27, arrangedoutside of said cylinder and pivoted to a suitable support, the

curved abutment 25, secured to said arm 27 and extending through saidstuffing-box into said cylinder and provided upon the oppo= site faceswith the steam-ports 35, the steampipes 37, and the steam-ports 36,communicating with said pipes 37 and with said ports and the piston 15,all substantially as described.

The main part of the port is 2. The combination, in a rotary engine,with the cylinder and piston, of the pivoted arm 27, the curved abutment25, secured to said arm and having the steam-passages 35 inits oppositefaces, the steam-pipes 37, and the steam-ports36,comrnunicatingwithsaidsteampassages 35, all substantially as described.

3. The combination, in a rotary engine, of the cylinder, the removableheads thereon, the removable cross-heads 11, the piston-shaft journaledon said cross-heads and having the splines 16, and the piston 15,secured upon said shaft by said splines and free to slide longitudinallythereon, arranged and operating substantially as described.

4. The combination, in a rotary engine, with the piston 15, of thering-packing 18 on the side of the piston, the adjustable packing 17 onthe end of the piston, and the packing 19, doweled to said packing 17and movable there- 20 with, arranged substantially as described.

5. The combination, in a rotary engine, with the steam-pipes 37, of thecylindrical steamchest 42,-connected with said pipes, the cylindricalvalve arranged in said cylinder and 25 having the T-shaped port 45, andthe V-shaped exhaustport 47, arranged andoperating sub stantially asdescribed.

In testimony whereof I have hereunto set my hand this 16th day ofFebruary, 1887.

EDWIN E. THOMAS.

In presence of- A. M. GASKELL, A. 0. PAUL.

